In a conventional process two implant steps are used to provide the lightly doped drain structure. Usually this process comprises a heavy implant of phosphorus followed by a light implant of arsenic into silicon. Here, however, after annealing, the junction depth is deep, typically greater than 0.5 .mu.m. It is a problem that these deep junctions degrade small channel length transistor performance, and such structures often prove to be unreliable.